9MW2821 in Combination With Toripalimab vs Standard Chemotherapy in Locally Advanced or Metastatic Urothelial Cancer

Inclusion Criteria: * Sign the informed consent form approved by IEC. * Male or female subjects aged 18 to 80 years. * ECOG status: 0 or 1. * Histologically confirmed local advanced or metastatic urothelial cancer * Previously untreated with local advanced or metastatic urothelial cancer * At least one measurable lesion, according to RECIST V1.1. * Adequate tumor tissues submitted for test * Suitable for cisplatin/carboplatin-based chemotherapy assessed by investigator * Life expectancy for more than 12 weeks. * Adequate organ functions. * Proper contraception methods. * Willingness to follow the study procedures. Exclusion Criteria: * History of another malignancy within 3 years. * History of autoimmune disease requiring systemic treatment within 2 years. * History of clinically significant cardiac/cerebrovascular diseases or thrombosis within 6 months. * Major surgery treated within 28 days; Any live vaccines got within 28 days; Radiotherapy or Intravesical therapy treated within 21 days; Traditional Chinese medicine or any potent CYP3A4 inducers/inhibitors taken within 14 days. * Lots of pleural fluid and ascites, uncontrolled bone pain or spinal compression existed within 14 days; Systemic treatment with active infection within 7 days. * Previously treated with PD-1, PD-L1, PD-L2, CTLA-4 inhibitors; Previously treated with ADCs which target Nectin-4 or are conjugated with payload MMAE; Organ transplantation or allogeneic hematopoietic stem cell transplantation in the past. * Clinical significantly toxicity Grade ≥ 2 (except alopecia and pigmentation) related to previous treatment. * Any situations adding the risk of severe dry eye, active keratitis or corneal ulcer, etc. * Peripheral neuropathy Grade ≥ 2. * Any other serious chronic or uncontrolled disease. * Uncontrolled central nervous system metastases or carcinomatous meningitis. * Active HBV/HCV/HIV infection, etc. * Known allergic sensitivity to any of the ingredients of the study drug. * History of drug abuse or mental illness. * Other conditions unsuitable into the study.